At the beginning of the War of Independence, Aldama was a captain of the cavalry regiment of the Queen's militia. He attended the conspiratorial meetings for independence in
Querétaro, organized by
Josefa Ortiz de Domínguez, despite having to travel from San Miguel el Grande (now San Miguel de Allende) in neighboring
Guanajuato.

Aldama was in San Miguel when he heard news that the conspiracy had been betrayed by a supporter who informed the Spanish colonial authorities. He traveled to
Dolores
(now Dolores Hidalgo) to informed Miguel Hidalgo y Costilla
and Ignacio Allende. He witnessed the
Grito de Dolores
("Cry of Dolores") on the night of September 16, 1810, which started the armed conflict.

Aldama was later captured by the Spanish colonial authorities in 1811. He was
court-martialed
for insubordination towards the Spanish Crown and executed for treason, by firing squad on June 26, 1811, together with Allende and other members of the rebel army including
Mariano Jiménez
and Manuel Santa María.